The invention is directed generally to polyolefin compositions having variable density properties and to methods of producing and using the same. More specifically, the invention relates to the use of density modulators and, in a preferred form to polymer-based compositions based on dicyclopentadiene (DCPD) and other cyclic olefins comprising such density modulators.
During the past 25 years, research efforts have enabled the elucidation of olefin metathesis reactions catalyzed by transition metal complexes. In particular, certain ruthenium and osmium carbene compounds have been identified as effective catalysts for olefin metathesis reactions such as, for example, ring opening metathesis polymerization (ROMP). Examples of such metathesis catalysts have been previously described in, for example, U.S. Pat. Nos. 5,312,940, 5,342,909, 5,728,917, 5,710,298, 5,831,108, and 6,001,909; PCT Publications WO 97/20865, WO 97/29135 and WO 99/51344; in United States Provisional Patent Application No. 60/142,713 filed Jul. 7, 1999 entitled xe2x80x9cROMP Reactions Using Imidazolidine-Based Metal Carbene Metathesis Catalysts;xe2x80x9d and by Furstner, Picquet, Bruneau, and Dixneuf in Chemical Communications, 1998, pages 1315-1316, the disclosures of each of which are incorporated herein by reference.
Density-modulated polymer compositions can be advantageous in a variety of applications, especially where xe2x80x9cweightxe2x80x9d or xe2x80x9cbalancexe2x80x9d of a polymeric part or article is a critical consideration. For example, density-modulated polymers would be useful materials for the production of equipment for the sports, recreation, and marine industries, particularly where dense, heavy articles or, alternatively, low-density, light foam articles are desired. Traditionally, numerous density-modulating additives have been used to effect these changes. However, where these traditional density modulators have been used in conjunction with typical thermoset or thermoplastic resins, numerous limitations or problems have arisen. Traditional thermoset resin systems lack inherent toughness and, once filled with conventional density modulators, become even more brittle in nature. Moreover, the high viscosity of these traditional resins prevents either the high loading of density modulators or the production of void-free articles. Thus, it has not been possible to combine the performance advantages provided by certain physical properties of polymers with the ability to vary the density of the polymer composition over a wide range without dramatically decreasing the practical value by increasing brittleness or void content of the articles produced.
In light of the foregoing, there exists a need for polymer compositions, and articles of made therefrom, which may be formulated to have variable densities for use in a wide range of commercial applications, especially those related to the sports, recreation, and marine industries.
This invention relates to novel polyolefin compositions having variable density, as well as to methods for producing and using the same. In particular, the invention provides for the inclusion of density modulators, which may be added to polyolefin resins. We have now found that these density modulators permit controllable modulation when used with a selected range of polymeric materials, of the density or xe2x80x9cweightxe2x80x9d of a resulting polyolefin article. Such modified polyolefin compositions are useful in a variety of applications and products, particularly those in the sports, recreational, and marine fields.
In certain preferred embodiments, the polyolefin compositions of the invention are prepared by the ring-opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) and related cyclic olefins, polymerized with a metal catalyst system. Ruthenium and osmium carbene compounds have been identified as effective catalysts for olefin metathesis reactions such as, for example, ROMP. Such metal carbene metathesis catalysts have been previously described in, for example, U.S. Pat. Nos. 5,312,940, 5,342,909, 5,728,917, 5,710,298, 5,831,108, and 6,001,909; PCT Publications WO 97/20865, WO 97/29135 and WO 99/51344; in United States Provisional Patent Application No. 60/142,713 filed Jul. 7, 1999 entitled xe2x80x9cROMP Reactions Using Imidazolidine-Based Metal Carbene Metathesis Catalysts;xe2x80x9d and by Fuirstner, Picquet, Bruneau, and Dixneuf in Chemical Communications, 1998, pages 1315-1316, the disclosures of each of which are incorporated herein by reference.
Examples of olefin monomers that may be polymerized using the aforementioned metathesis catalysts include dicyclopentadiene (DCPD), in addition to other cyclic olefin compounds. Polymer compositions, and articles or parts produced therefrom, are useful in a wide variety of applications because of their unique physical properties and ease of fabrication. In particular, DCPD-based polymer (poly-DCPD) compositions show promise for applications requiring a combination of toughness, hardness, variable density, and/or corrosion resistance. In addition, the low viscosity of DCPD-based compositions makes these resins particularly well-suited to the fabrication of complex shapes and composites.
In preferred embodiments, the invention involves ROMP reactions where olefin (such as DCPD resin) compositions are cast into product molds or infused into a fiber preform. For certain applications, pigments, dyes, antioxidants, flame retardants, toughness modulators, hardness modulators, among other additives, may optionally be included in the polyolefin composition. In its preferred forms, the invention includes two main groups of modified polyolefin compositions: (1) polyolefin compositions that are lighter in density or weight than the unmodified polyolefin resins and (2) polyolefin compositions that are higher in density or weight than the unmodified polyolefin resins. The modulating additives are dispersed in the polyolefin resin matrix to alter various physical properties of the native polyolefin.
Particularly preferred density modulators include, for example, metallic density modulators (in the case of increased-density polyolefin compositions), microparticulate density modulators, such as, for example, microspheres (in the case of increased- or decreased-density polyolefin compositions), and macroparticulate density modulators, such as, for example, glass or ceramic beads (in the case of increased- or decreased-density polyolefin compositions). Metallic density modulators include, but are not limited to, powdered, sintered, shaved, flaked, filed, particulated, or granulated metals, metal oxides, metal nitrides, and/or metal carbides, and the like. Microparticulate density modulators include, but are not limited to, glass, metal, thermoplastic (either expandable or pre-expanded) or thermoset, and/or ceramic/silicate microspheres. Macroparticulate density modulators include, but are not limited to, glass, plastic, or ceramic beads; metal rods, chunks, pieces, or shot; hollow glass, ceramic, plastic, or metallic spheres, balls, or tubes; and the like. Density modulators of the invention may optionally comprise sizings, finishes, coatings, and/or surface treatments to enhance their compatibility with and/or adhesion to the polyolefin matrix resins.
One aspect of the invention is a novel polyolefin composition having variable density properties through the addition of density modulators. Another aspect of the invention is a process for preparing such variable-density polyolefin compositions, wherein the process includes the step of adding to a polyolefin resin various density modulators. A further aspect is an article of manufacture, such as a molded part, comprising the aforementioned polyolefin composition. These and other aspect of the invention will be apparent to one skilled in the art in light of the following detailed description of the preferred embodiments.
The invention is directed to polyolefin compositions having variable density properties and to methods for their production and use. In certain embodiments, the invention provides for density modulators, which may be added to polyolefin resins to alter various physical properties. More specifically, addition of density modulators allows controllable modulation of the density or xe2x80x9cweightxe2x80x9d of a polyolefin article. Such modified polyolefin compositions are useful in a wide variety of applications, particularly for use in sports, recreation, and marine equipment products.
The polyolefin compositions of the invention may be prepared by the metathesis of olefin monomers such as DCPD and related cyclic olefins, polymerized with a metal catalyst system. Ruthenium and osmium carbene compounds have been identified as effective catalysts for olefin metathesis reactions such as, for example, ring opening metathesis polymerization (ROMP) and are described in the patents and other references noted above, as is known in the art.
Any suitable metathesis catalyst may be used. One example of a ruthenium or osmium metal carbene catalyst that may be used with the invention possesses metal centers that are formally in the +2 oxidation state, have an electron count of 16, are penta-coordinated, and are of the general formula 
wherein:
M is ruthenium or osmium;
X and X1 are each independently any anionic ligand;
L and L1 are each independently any neutral electron donor ligand;
R and R1 are each independently hydrogen or a substitutent selected from the group consisting of C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl and C1-C20 alkylsulfinyl. Optionally, each of the R or R1 substitutent group may be substituted with one or more moieties selected from the group consisting of C1-C10 alkyl, C1-C10 alkoxy, and aryl which in turn may each be further substituted with one or more groups selected from a halogen, a C1-C5 alkyl, C1-C5 alkoxy, and phenyl. Moreover, any of the catalyst ligands may further include one or more functional groups. Examples of suitable functional groups include but are not limited to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.
In preferred embodiments of these catalysts, the R substitutent is hydrogen and the R1 substitutent is selected from the group consisting C1-C20 alkyl, C2-C20 alkenyl, and aryl. In even more preferred embodiments, the R1 substitutent is phenyl or vinyl, optionally substituted with one or more moieties selected from the group consisting of C1-C5 alkyl, C1-C5 alkoxy, phenyl, and a functional group. In especially preferred embodiments, R1 is phenyl or vinyl substituted with one or more moieties selected from the group consisting of chloride, bromide, iodide, fluoride, xe2x80x94NO2, xe2x80x94NMe2, methyl, methoxy and phenyl. In the most preferred embodiments, the R1 substitutent is phenyl.
In preferred embodiments of these catalysts, L and L1 are each independently selected from the group consisting of phosphine, sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine, stibine, ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl, pyridine, and thioether. In more preferred embodiments, L and L1 are each a phosphine of the formula PR3R4R5, where R3, R4, and R5 are each independently aryl or C1-C10 alkyl, particularly primary alkyl, secondary alkyl or cycloalkyl. In the most preferred embodiments, L and L1 ligands are each selected from the group consisting of xe2x80x94P(cyclohexyl)3, xe2x80x94P(cyclopentyl)3, xe2x80x94P(isopropyl)3, and xe2x80x94P(phenyl)3. Another preferred embodiment of the catalyst is where L is any neutral electron donor and L1 is an imidazolidine ligand. In certain embodiments, L1 may have the general formula 
wherein:
R2, R3, R4, and R5 are each independently hydrogen or a substituent selected from the group consisting of C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, aryl, C1-C20 carboxylate, C1-C20 alkoxy, C2-C20 alkenyloxy, C2-C20 alkynyloxy, aryloxy, C2-C20 alkoxycarbonyl, C1-C20 alkylthio, C1-C20 alkylsulfonyl and C1-C20 alkylsulfinyl. R3 and R4 may also together form a cycloalkyl or an aryl moiety. A preferred embodiment is where R3 and R4 are both hydrogen or phenyl and R2 and R5 are each independently substituted or unsubstituted aryl. In addition, L and L1 together may comprise a bidentate ligand.
In preferred embodiments of these catalysts, X and X1 are each independently hydrogen, halide, or one of the following groups: C1-C20 alkyl, aryl, C1-C20 alkoxide, aryloxide, C3-C20 alkyldiketonate, aryldiketonate, C1-C20 carboxylate, arylsulfonate, C1-C20 alkylsulfonate, C1-C20 alkylthio, C1-C20 alkylsulfonyl, or C1-C20 alkylsulfinyl. Optionally, X and X1 may be substituted with one or more moieties selected from the group consisting of C1-C10 alkyl, C1-C10 alkoxy, and aryl which in turn may each be further substituted with one or more groups selected from halogen, C1-C5 alkyl, C1-C5 alkoxy, and phenyl. In more preferred embodiments, X and X1 are halide, benzoate, C1-C5 carboxylate, C1-C5 alkyl, phenoxy, C1-C5 alkoxy, C1-C5 alkylthio, aryl, and C1-C5 alkyl sulfonate. In even more preferred embodiments, X and X1 are each halide, CF3CO2, CH3CO2, CFH2CO2, (CH3)3CO, (CF3)2(CH3)CO, (CF3)(CH3)2CO, PhO, MeO, EtO, tosylate, mesylate, or trifluoromethanesulfonate. In the most preferred embodiments, X and X1 are each chloride. In addition, X and X1 together may comprise a bidentate ligand.
The catalyst:olefin monomer ratio in the invention is preferably is in a range of about 1:100 to about 1:1,000,000. More preferably, the catalyst:monomer ratio is in a range of about 1:1,000 to about 1:150,000 and, most preferably, is in a range of about 1:3,000 to about 1:60,000. Particularly preferred metal catalysts include, but are not limited to, bis(tricyclohexylphosphine) benzylidene ruthenium dichloride, bis(tricyclohexylphosphine) dimethylvinylmethylidene ruthenium dichloride, bis(tricyclopentylphosphine) dimethylvinylmethylidene ruthenium dichloride, (tricyclohexylphosphine)(1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) benzylidene ruthenium dichloride, (tricyclopentylphosphine)(1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride, (tricyclohexylphosphine)(1,3-dimesityl-4,5-dihydroimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride, (tricyclohexylphosphine)(1,3-dimesitylimidazol-2-ylidene) benzylidene ruthenium dichloride, (tricyclopentylphosphine)(1,3-dimesitylimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride, and (tricyclohexylphosphine)(1,3-dimesitylimidazol-2-ylidene) dimethylvinylmethylidene ruthenium dichloride.
The invention includes two principal types of modified polyolefin compositions: (1) polyolefin compositions that are lighter in density or weight than the unmodified polyolefin resins and (2) polyolefin compositions that are higher in density or weight than the unmodified polyolefin resins. The modulating additives are dispersed in the polyolefin resin matrix to alter various physical properties of the native polyolefin. In the case of polyolefin compositions containing density modulators, the density or xe2x80x9cweightxe2x80x9d of an article may be controllably varied to suit a particular application by altering the identity and amount of the density modulator. In the case of polyolefin compositions containing hardness and/or toughness modulators, various physical properties of an article, including hardness, toughness, elasticity, and surface xe2x80x9cfeel,xe2x80x9d may be varied to suit a given application. Hardness and/or toughness modified polyolefin compositions are described in U.S. patent application Ser. No. 09/312,811 filed May 17, 1999 entitled xe2x80x9cPolyolefin Compositions Optionally Having Variable Toughness and/or Hardness;xe2x80x9d all of which is incorporated herein by reference. For certain applications and products (e.g., weighted golf club heads), polyolefin hybrids containing density, hardness, and toughness modulators may be preferred. Hybrid modified poly-DCPD articles can combine, for example, increased density with increased toughness.
Density modulators include, for example, metallic density modulators (in the case of increased-density polyolefin compositions), microparticulate density modulators, such as, for example, microspheres (in the case of increased- or decreased-density polyolefin compositions), and macroparticulate density modulators, such as, for example, glass or ceramic beads (in the case of increased- or decreased-density polyolefin compositions). Metallic density modulators include, but are not limited to, powdered, sintered, shaved, flaked, filed, particulated, or granulated metals, metal oxides, metal nitrides, and/or metal carbides, and the like. Preferred metallic density modulators include, among others, tungsten, tungsten carbide, aluminum, titanium, iron, lead, silicon oxide, aluminum oxide, boron carbide, and silicon carbide. Microparticulate density modulators include, but are not limited to, glass, metal, thermoplastic (either expandable or pre-expanded) or thermoset, and/or ceramic/silicate microspheres. Macroparticulate density modulators include, but are not limited to, glass, plastic, or ceramic beads; metal rods, chunks, pieces, or shot; hollow glass, ceramic, plastic, or metallic spheres, balls, or tubes; and the like. Density modulators of the invention may optionally comprise sizings, finishes, coatings, and/or surface treatments to enhance their compatibility with and/or adhesion to the polyolefin matrix resins. Particularly preferred are the use of adhesion agents to increase adhesion between the density modulators and polyolefin resins. Such adhesion agents are described in, for example, U.S. Provisional Patent Application Serial No. 60/118,864, filed Feb. 5, 1999, and U.S. patent application Ser. No. 09/497,774, filed Feb. 4, 2000, entitled xe2x80x9cMetathesis-Active Adhesion Agents and Methods for Enhancing Polymer Adhesion to Surfaces,xe2x80x9d the contents of each of which are incorporated herein by reference.
The density modulator(s) may be dispersed in the polyolefin resin matrix by stirring or mixing with the olefin monomer(s) and then polymerizing the mixture using a metathesis or metal carbene catalyst. Alternatively, the olefin monomer(s) may be infused into a bed or preform of the density modulator(s) and then polymerized using a metathesis or metal carbene catalyst. The density, wear resistance and/or xe2x80x9cfeelxe2x80x9d of a density-modulated poly-DCPD composite may be varied in a controllable manner. For example, poly-DCPD compositions containing aluminum metal powder have a soft surface xe2x80x9cfeelxe2x80x9d, while poly-DCPD compositions containing aluminum oxide have a rough surface and are extremely wear-resistant. Similarly, poly-DCPD compositions containing thermoplastic microspheres are very tough with a soft xe2x80x9cfeel,xe2x80x9d while poly-DCPD compositions containing glass microspheres are harder and stiffer. In the case of density-modulated poly-DCPD composite resins, articles or parts made therefrom may be produced to be isotropic, where the density modulator is dispersed evenly throughout the article or part, or anisotropic, where the density modulator is dispersed unevenly (either through the use of layers or a density gradient). For certain articles, it will be preferred that the density-modulated composition possess a thin layer (or skin) of neat resin at the surface to enhance appearance, toughness, corrosion resistance, or other properties.
The amount of metallic density modulator(s) included in the polyolefin compositions of the invention is about 1% to about 99% by volume. Preferably, the amount of density modulator(s) is about 20% to about 90% by volume and most preferably, is about 30% to about 80% by volume. In cases where extreme density modulation is of utmost importance, the amount of density modulator(s) is preferably about 60% to about 95% by volume. Using the volume percentage, one skilled in the art can determine the appropriate weigh fraction to use based on the known densities of the resin and the density modulator used. For example, the amount of metallic density modulator included in the polyolefin compositions of the invention is preferably about 1 to about 17000 parts per hundred resin(phr) by weight. More preferably, the amount of metallic density modulator is about 50 to about 7500 phr and, most preferably, is about 100 to about 1000 phr. The amount of microparticulate density modulator included in the polyolefin compositions of the invention is preferably about 1 to about 1000 phr by weight. More preferably, the amount of microparticulate density modulator is about 10 to about 500 phr and, most preferably, is about 20 to about 250 phr. The amount of macroparticulate density modulator included in the polyolefin compositions of the invention is preferably about 1 to about 5000 phr by weight. More preferably, the amount of macroparticulate density modulator is about 10 to about 1000 phr and, most preferably, is about 20 to about 500 phr.
In the case of microparticulate density modulators, the poly-olefin resin compositions of the invention have numerous advantages over traditional thermoset polymers (e.g., epoxies, vinyl esters, unsaturated polyesters, urethanes, and silicones) in the fabrication of low- to medium-density syntactic foams. Syntactic foams are known to those skilled in the art but generally describe a cellular polymer produced by dispersing microscopic particles in a fluid polymer and then stabilizing the system. Specifically, these poly-olefin resins combine low viscosity (e.g.,  less than 20 centipoise), long gelling times (e.g.,  greater than 20 minutes), high inherent toughness, and high tensile strength. The low density and viscosity of the poly-olefin resins of the invention permit better wetout and packing of the microspheres, resulting in improved physical properties and, simultaneously, decreased densities (preferably, about 5%-30% decrease), compared to current state-of-the-art conventional resin systems.
The most preferred olefin monomer for use in the invention is dicyclopentadiene (DCPD). Various DCPD suppliers and purities may be used such as Lyondell 108 (94.6% purity), Veliscol UHP (99+% purity), B. F. Goodrich Ultrenee (97% and 99% purities), and Hitachi (99+% purity). Other preferred olefin monomers include other cyclopentadiene oligomers including trimers, tetramers, pentamers, and the like; cyclooctadiene (COD; DuPont); cyclooctene (COE, Alfa Aesar); cyclohexenylnorbornene (Shell); norbornene (Aldrich); norbornene dicarboxylic anhydride (nadic anhydride); norbornadiene (Elf Atochem); and substituted norbornenes including butyl norbornene, hexyl norbornene, octyl norbornene, decyl norbornene, and the like. Preferably, the olefinic moieties include mono- or disubstituted olefins and cycloolefins containing between 3 and 200 carbons. Most preferably, metathesis-active olefinic moieties include cyclic or multicyclic olefins, for example, cyclopropenes, cyclobutenes, cycloheptenes, cyclooctenes, [2.2.1]bicycloheptenes, [2.2.2]bicyclooctenes, benzocyclobutenes, cyclopentenes, cyclopentadiene oligomers including trimers, tetramers, pentamers, and the like; cyclohexenes. It is also understood that such compositions include frameworks in which one or more of the carbon atoms carry substituents derived from radical fragments including halogens, pseudohalogens, alkyl, aryl, acyl, carboxyl, alkoxy, alkyl- and arylthiolate, amino, aminoalkyl, and the like, or in which one or more carbon atoms have been replaced by, for example, silicon, oxygen, sulfur, nitrogen, phosphorus, antimony, or boron. For example, the olefin may be substituted with one or more groups such as thiol, thioether, ketone, aldehyde, ester, ether, amine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, phosphate, phosphite, sulfate, sulfite, sulfonyl, carboiimide, carboalkoxy, carbamate, halogen, or pseudohalogen. Similarly, the olefin may be substituted with one or more groups such as C1-C20 alkyl, aryl, acyl, C1-C20 alkoxide, aryloxide, C3-C20 alkyldiketonate, aryldiketonate, C1-C20 carboxylate, arylsulfonate, C1-C20 alkylsulfonate, C1-C20 alkylthio, arylthio, C1-C20 alkylsulfonyl, and C1-C20 alkylsulfinyl, C1-C20 alkylphosphate, arylphosphate, wherein the moiety may be substituted or unsubstituted.
These olefin monomers may be used alone or mixed with each other in various combinations to adjust the properties of the olefin monomer composition. For example, mixtures of cyclopentadiene dimer and trimers offer a reduced melting point and yield cured olefin copolymers with increased mechanical strength and stiffniess relative to pure poly-DCPD. As another example, incorporation of COD, norbornene, or alkyl norbornene comonomers tend to yield cured olefin copolymers that are relatively soft and rubbery. The polyolefin resins of the invention are amenable to thermosetting and are tolerant of additives, stabilizers, rate modifiers, hardness and/or toughness modifiers, fillers and fibers including, but not limited to, carbon, glass, aramid (e.g., Keylar(copyright) and Twaron(copyright)), polyethylene (e.g., Spectra(copyright) and Dyneema(copyright)), polyparaphenylene benzobisoxazole (e.g., Zylon(copyright)), polybenzamidazole (PBI), and hybrids thereof as well as other polymer fibers.
In the invention, the viscosity of the formulated olefin monomers (e.g., the olefin monomers combined with any additives, stabilizers, or modifiers other than density modulators, fillers, or fibers) is typically less than about 2,000 centipoise at temperatures near room temperature (e.g., from about 25-35xc2x0 C.). Preferably, the viscosity of the formulated olefin monomers is less than about 500 centipoise, more preferably is less than about 200 centipose, and most preferably, is less than about 75 centipoise. The viscosity of the formulated olefin monomers can be controlled by selection of the combination of monomers and additives, stabilizers, and modifiers used.
Preferred hardness modulators include, for example, elastomeric additives such as polybutadienes, polyisoprenes, and the like. Polybutadienes and polyisoprenes of various sources, as well as various number-average molecular weights (Mn) or weight-average molecular weights (Mw), may be utilized in the invention as rubber-like hardness modulators. Unexpectedly, the poly-DCPD resins of the invention allow compositions containing polybutadiene to be clear rather than opaque. The hardness modulators of the invention, when added to a polyolefin resin composition, alter the hardness, toughness and/or surface xe2x80x9cfeelxe2x80x9d of the composition compared to the unmodified or native polyolefin. In addition to butadiene and isoprene-based elastomers, other hardness modulators include plasticizers such as dioctyl phthalate and various molecular weight hydrocarbon and the like jellies, greases and waxes, carboxylic acids and salts thereof, and co-monomers such as norbornene, cyclooctadiene, cyclooctene, cyclohexenylnorbornene, norbornadiene, cyclopentene and/or methylcyclopentene. The amount of hardness modulator included in the polyolefin compositions of the invention is preferably about 0.1%-20% by weight of the olefin monomer to which it is added. More preferably, the amount of hardness modulator is about 1%-10% by weight of the olefin monomer and, most preferably, is about 2.5%-7.5%.
Especially preferred toughness modulators are rubber triblock copolymers such as styrene-butadiene-styrene, styrene-isoprene-styrene, styrene-ethylene/butylenes-styrene, styrene-ethylene/propylene-styrene, and the like. Other preferred toughness modulators include polysiloxanes, because the resulting polyolefin compositions possess significantly increased toughness properties without significant concomitant losses in heat distortion temperature (HDT). The amount of toughness modulator included in the polyolefin compositions of the invention is preferably about 0.1%-10% by weight of the olefin monomer to which it is added. More preferably, the amount of toughness modulator is about 0.5%-6% by weight of the olefin monomer and, most preferably, is about 2%-4%. For example, poly-DCPD resins containing 3 parts per hundred low molecular weight (MW) poly(dimethylsiloxane) (Shin Etsu DMF-50) possess notched Izod impact values in excess of 4 ft.-lb./in. and HDT values above 130xc2x0 C.
The UV and oxidative resistance of the polyolefin compositions of the invention may be enhanced by the addition of various stabilizing additives such as primary antioxidants (e.g., sterically hindered phenols and the like), secondary antioxidants (e.g., organophosphites, thioesters, and the like), light stabilizers (e.g., hindered amine light stabilizers or HALS), and UV light absorbers (e.g., hydroxy benzophenone absorbers, hydroxyphenylbenzotriazole absorbers, and the like). Preferably, one or more stabilizing additives are included in the polyolefin resin composition at a level from about 0.01-15 phr. More preferably, the antioxidant(s) are present at a level of about 0.05-10 phr and, most preferably, 0.1-8 phr. Exemplary primary antioxidants include, for example, 4,4xe2x80x2-methylenebis (2,6-di-tertiary-butylphenol) (Ethanox 702(copyright); Albemarle Corporation), 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (Ethanox 330(copyright); Albermarle Corporation), octadecyl-3-(3xe2x80x2,5xe2x80x2-di-tert-butyl-4xe2x80x2-hydroxyphenyl)propionate (Irganox 1076(copyright); Ciba-Geigy), and pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate)(Irganoxo(copyright) 1010; Ciba-Geigy). Exemplary secondary antioxidants include tris(2,4-ditert-butylphenyl)phosphite (Irgafos(copyright) 168; Ciba-Geigy), 1:11 (3,6,9-trioxaudecyl)bis(dodecylthio)propionate (Wingstay(copyright) SN-1; Goodyear), and the like. Exemplary light stabilizers and absorbers include bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate (Tinuvin(copyright) 144 HALS; Ciba-Geigy), 2-(2H-benzotriazol-2-yl)-4,6-ditertpentylphenol (Tinuvin(copyright) 328 absorber; Ciba-Geigy), 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenyl (Tinuvin(copyright) 327 absorber; Ciba-Geigy), 2-hydroxy-4-(octyloxy)benzophenone (Chimassorb(copyright) 81 absorber; Ciba-Geigy), and the like.
In addition, a suitable rate modifier such as, for example, triphenylphosphine (TPP), tricyclopentylphosphine, tricyclohexylphosphine, triisopropylphosphine, trialkylphosphites, triarylphosphites, mixed phosphites, pyridine, or other Lewis base, may be added to the olefin monomer to retard or accelerate the rate of polymerization as required. In the case of TPP rate modifier, it is preferably included in an amount of about 10-200 mg: per 64 g olefin monomer. More preferably, the amount of TPP is about 20-100 mg per 64 g olefin monomer and, most preferably, is about 30-80 mg per 64 g olefin monomer. In the case of other rate modifiers, such as alkylphospines and pyridine, the amount of rate modifier is preferably about 0.1-50 mg per 64 g olefin monomer, more preferably about 1-40 mg:64 g olefin monomer, and most preferably is about 1-30 mg per 64 g olefin monomer.
Also, various pigments or dyes may be included in the polyolefin resin compositions of the invention for applications where color is desired. Preferred pigments include Ferro and Dayglo products, in an amount of about 0.05-2 parts per hundred of polyolefin resin. A particularly preferred class of dyes are photochromic dyes.
The polyolefin compositions, and parts or articles of manufacture prepared therefrom, may be processed in a variety of ways including, for example, Reaction Injection Molding (RIM), Resin Transfer Molding (RTM) and vacuum-assisted variants such as VARTM (Vacuum-Assisted RMT) and SCRIMP (Seemann Composite Resin Infusion Molding Process), open casting, rotational molding, centrifugal casting, filament winding, and mechanical machining. These processing compositions are well known in the art. Various molding and processing techniques are described, for example, in PCT Publication WO 97/20865, the disclosure of which is incorporated herein by reference. In mold casting processes, the mold may be constructed of various materials including, for example, aluminum, teflon, delrin, high- and low-density polyethylenes (HDPE and LDPE, respectively), silicone, epoxy, aluminum-filled epoxy, polyurethane and aluminum-filled polyurethane, plaster, polyvinylchloride (PVC), and various alloys of stainless steel. The mold temperature is preferably about 20-100xc2x0 C., more preferably about 30-80xc2x0 C., and most preferably about 40-60xc2x0 C. The molded polyolefin part or article of the invention may also be subjected to a post-cure heating step. Preferably, the post-cure involves heating to about 60-160xc2x0 C. for about 10 minutes-3 hours. More preferably, the post-cure involves heating to about 80-150xc2x0 C. for about 30 minutes-2 hours and, and most preferably, involves heating to about 100-140xc2x0 C. for between about 45 and about 90 minutes.
The polyolefin compositions of the invention are useful in the production of sports, recreation, and marine products and equipment. Examples of such products and applications include, but are not limited to, the following: golf tees, clubs (including weighted club heads), shafts, gradient shafts (where the formulation or density varies along the length of the club shaft), balls, and carts; basketball backboards; tennis rackets, squash rackets, racquetball rackets, and badminton racquets; snow boards, surfboards, boogie boards, skis, backboards, sleds, toboggans, snow shoes; baseball bats, bat coatings and end-caps, balls, and helmets; football helmets; hockey helmets, sticks, pads, and pucks; roller blade shoes, wheels, pads, and helmets; bicycle parts, frames, helmets, and trispokes; marine applications (e.g., hulls, coatings, oars, propellers, rudders, keels, masts, jet skis, boat fascia, jet skis, covers, kayaks, and canoes); camping equipment (e.g., tent stakes and supports, tubs, matches, coolers, wedges for splitting wood, axes, hatchets, handles, shovels, and picks); pool cues, pool tables, and pool balls; diving boards, pool liners, lake liners, ladders, steps, floating lounge chairs and tables, pool cleaning equipment, and lounge chairs; motorcycles, motorcycle parts, helmets, and shields; archery bows and arrows; guns, rifle cases, butts, bullets, shotgun pellets, decoys, ammunition and shell cases; martial arts protective padding and weapons; soccer goal posts and pads; auto racing helmets, car parts, and bodies; polo mallets, croquet mallets and balls, and cricket bats; gaming accessories (e.g., poker chips, dice, and weather resistant game boards); bowling balls and pins; tether ball pole, net supports in volleyball; All Terrain Vehicles (ATV); lawn darts, quoits, and horseshoes; and knives, knife handles, and swords. In particular, foams of various densities are useful in numerous applications where properties such as weight, buoyancy, acoustic impedance, anticorrosion, antifouling, and low moisture absorption are considerations.
Other commercial applications for the invention include, for example, ballistics and blast containment, industrial coatings, architectural coatings, and other scratch resistant coatings, adhesives, inks, paints, and gel coats. Additionally, the compositions of the invention are useful in polymer mixtures, interpenetrating polymer networks, composites (fiber or mineral reinforced), blends, alloys, elastomers, ionomers, and dendrimers, among others.
The compositions of the invention are also useful in the manufacture of wafer carriers and other semiconductor handling equipment, as well as parts for the construction of semiconductor fabrication facilities, such as walls, fascia, sinks, and decking. Additionally, these materials are useful as low k dielectrics and components for chemical/mechanical planarization (CMP).
In addition, the polyolefin resins may be used with adhesion agents, for example, metathesis active adhesion agents with compatibilizing functionalities for interacting with a substrate surface.
In the case of polyolefin compositions or parts comprising metallic density modulators, the invention permits the advantageous control of balance, weight and density localization. These capabilities provide for the enhancement of the performance of, for example, golf club heads and putters and composite tooling, through selective addition and location of metallic density modulators.
In the case of polyolefin compositions or parts comprising microparticulate density modulators (i.e., syntactic foam), advantages of the compositions of the invention are evidenced in the lightweight support and flexion enhancement of sports equipment such as archery bows, bats, sticks, and shafts. Other preferred uses for the syntactic foams of the invention include hulls and other components of boats and submersibles, core materials for skis and surf-, snow-, and skateboards, and lightweight reinforcement of safety equipment such as pads and helmets.